Method and apparatus for forming concrete piles



L. LAWTON 3,209,546 METHOD AND APPARATUS FOR FORMING CONCRETE FILESJNVENTOR. LAWRENCE LAWTON 3 Sheets-Sheet l Filed Sept. 21, 1960 ATTORNEYL. LAWTON 32%,546 METHOD AND APPARATUS FOR FORMING CONCRETE PILES Get. 5E9 65 3 Shae-0561166 2 Filed Sept. 21, 1960 INVENTOR. LAJRENCE LAWTONATTORNEY @cfi. 5, 3%5 L. LAWTON 34$ METHOD AND APPARATUS FOR FORMINGCONCRETE FILES Filed Sept. 21. 196a 3 Sheets-Sheet 3 IN V EN TOR.LAWREEJCE LAWTON 1. 43% hawk,

ATTORNEY diillifillh Patented Get. .5, 1965 3,209,546 METHGD ANDAPPARATUS Fill? FGG CGNCRETE FILES Lawton, 150-47 Village Road, Jamaica,N.Y. Filed- Sept. 21, 1960, Ser. No. 57,573 '8 Claims. (Cl. 61-536)Lawrence of what action may have taken place underground during theforming of the pedestal.

Among the objects of the present invention is to avoid faultsexperienced from prior practices and unnecessary expense incidentthereto; to remove the element of unpredictability in the forming of adesired footing; and.

to provide a concrete pedestal pile having a' footing of concrete,homogeneous throughout, and a dependable spread or effective horizontalbearing area. The foregoing and other results are attained in accordancewith the present invention in an efiicient manner with a great degree ofreliabilityas a consequence of the procedure employed to form thepedestal.

The procedure includes the employment of a steel shell having arelatively rigid and inexpansible upper section or shaft casing andanexpansible lower section or pedestal casing. The section of the shellfrom which the shape and size of the pedestal is derived is so constructed that when it has been expanded to the shape of a pedestal itis, of itself, resistant to distortionfrom the action of externalforceswithout the assistance of internal pressure, or a filling ofconcrete. As a consequence, a number of pile shells can be driven andcompletely formed before they are filled. A group of shells may beprepared for filling and then filled at the convenience of the operator.

The wall of the lower section is crimped throughout its circumferencewith bellows-like folds forming ribs running lengthwise of the shell.The upper and lower ends of the expansible section are welded to heavyrings which are welded respectively to the upper section of the shelland to a closure or shoe in a manner to provide pressure-tightconnections with the rigid section or shaft casing and with the closure.

The expansible casing is expanded after the shell has been placed in theground. lnteriorly applied fluid pressure, whose intensity exceeds thepassive resistance to horizontal thrust of the soil at the elevation ofthe pedestal casing, forces the wall of the pedestal casing outwardlyinto a bulbous shape between its ends. The transverse bends of theoriginal folds provide an expanded wall having ribbed metal arches,because of the uniform distribution and constant intensity of fluidpressure. This arched construction is highly resistant to collapse frompressure directed from the outside. The action of these vertical archesin resisting collapse is enhanced by the lateral support aiiorded by thehorizontal continuity of the arched ribs.

The original folds strengthen the expansible casing suhiciently to avoidvertical collapse from the blows of a driving hammer. The verticalcollapse of an inexpansible upper casing made of light gauge materialcan be avoided by employing a core to receive and transmit the drivingforce to a drive shoe. Advantages of the vention are attainable from theuse of a core or of an expandable mandrel carrying devices fordetermining the dimensions of the chamber which is subsequently formedwhen the lower section is expanded.

After the shell has been fully driven, the core or mandrel is raised apredetermined distance. Temporary sealing means are made to cooperatebetween the exterior of the core or internal element of the mandrel andthe interior of the shell above the expansible section to efiectivelyseal off a pressure-tight chamber. The expansible section of the shellis then expanded by introducing a pressurized fluid to the interior ofthe chamber.

The extent of expansion of the pedestal casing is determinable withoutdiscontinuing the pressure. It can be determined by measuring thequantity of the pressurizing fluid used or by devices which are mountedupon the core and are extendable to engage the interior of the expandedcasing. By such means it is possible accurately to determine the lateraldisplacement of the arched walls at any time. When the expansible wallshave been displaced a predetermined desired amount, the internalpressure is relieved, the sealing means are collapsed, and the core andall of the attached appurtenances are withdrawn from the prepared shell.Concrete is introduced within the shell to complete the installation ofthe pile. The concrete of the resulting pile has a footing of knownpropor-' tions and is wholly enveloped with sheet steel which is anintegral part of the pile.

Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself, as to its objects and advantages, and themanner in which it may he carried out, may be better understood byreferring to the following description taken in connection with theaccompanying drawing, in which:

FIG. .1 is a vertical sectional view or" a pile shell which has beencapped preliminarily to the application of pressure to its interior;

FIG. 2 is a vertical sectional view of a pile shell containing a drivingcore;

FIG. 3 is a view similar to FIG. 2 with the driving core raisedpreliminarily to the introduction of pressurized fluid to the lowerportion of the shell;

PEG. 4 is a view similar to that of FIG. 3 and illustrating an expandedposition of the expansible section;

FIG. 5 is a vertical section taken on the axis of a completed pile;

FIGS. 6, 7 and 8 are enlarged sectional views taken approximately onlines 6-45, 7-7 and 3-3, respectively, of FIG. 4; and

FIG. 9 is a horizontal section taken through the expandable mandrel online 9-9 of FIG. 4.

Referring first to FlG. l, the shell shown consists essentially oi asubstantially inexpansible upper section Iii), an expansioie lowersection ill. and a closure 12 sealing the lower end of the lowersection. The upper section is in the form of an impermeable hollowcylinder or casing 33 and may conform with usual specifications for pileshells for withstanding blows from a hammer, or for placement in theground by a core or mandrel. The expansible section includes a casing il crirnped with deep folds running vertically and defining ridges 15separated by valleys (E6. 7). The folds in the casing 14 may be producedby impressing a sheet of steel of a predetermined width, curving thesheet into a cylinder and welding the longitudinal edges of the sheet toform an imp meable sleeve. The folds extend to opposite edges o e sheet,but they may be made to terminate short thereof, if desired, dependingon the method employed for forming them. T he width of a sheer beforecrimp ng, or no quantity of material around the sleeve, must be astequal to, and is preferably greater than, the maxnnum girth desired forthe pedestal.

ne we.

. The vertical folds adjacent theuppcr edges of the expansible casing 14are swaged or laid over to fit against and engage with the interior of aheavy spacing ring 18, as best seen in FIG. 6. The ring 18 is welded tothe casing 14 and the'weld material 19 is used to fill the intersticesbetween the closed folds and the ring so as to provide a pressure-tightconnection entirely around the ring. The upper casing 13 is also weldedat 20 to the ring 18 entirely around the ring.

Pressure-tight joints with-a heavy ring 21 at the lower end of thecasing 14 are made in like manner. The lower end of the expansiblecasing 14 is also swaged to flatten and lay the folds against the ring21to which the casing is welded. Welding metal 22 completes a leak-proofseal between the ring and the casing.

The shoe or point 12 may be shaped in any suitable form. It fully closesand seals the lower end of the section to which it is permanentlyattached by welding. It is desirable that the outer diameter of the shoeor of the ring 21 be sufiiciently greater than the maximum unexpandeddiameter of the casing 14 to provide enough clearance around the casingto avoid excessive drag of the soil on the casing, or damage to thecasing.

The folds of the casing 14 are formed into deep ribs to provide a highsection modulus and beam strength for resisting bending stresses.- Thecasing is made of metal, preferably of sheet steel having sufiicientductility to avoid rupture in the process of expanding under difiicultsoil conditions. The swaging of the ends of a crimped sectionreduces thedepth of the ribs and consequently the section modulus in the vicinityof the rings and facilitates outward bending of the wall of the sectionadjacent the heavy rings when the section is subjected to fluid pressureduring the expanding operation. The showing in FIG. 1 is illustrative ofone manner of creating a pressure-tight chamber within a shell. Theshell has been capped with ahead 23 which functions as a plug closurethrough which fluid pressure may be applied to the interior of theshell. The shell may have been placed in an open hole, or it may havebeen driven either by hammer blows directed against the upper end of theshell, or against a driving core which has been removed. The head 23consists of a block of metal which rests upon the top of the shell andhas'a hub extending within the shell. An annular recess 25 about the hubcontains a circular bladder 26 in the form of a hollow torus. Thisbladder is inflatable to seal the space between the hub and the interiorof the shell. Pneumatic pressure is applied to the bladder through pipes27 and 28.

The head is bored to receive a union 29 connected to a pipe 30 throughwhich compressed air is supplied to the interior of the shell. In thisexample, the entire length of the shell is subjected to pneumaticpressure which is employed to expand the expansible casing at the lowerend of the shell. eyes fastened to the clamp and to the head,respectively, secure the head to the shell to prevent displacement ofthe head. The head and shell can be additionally weighted by a hammer33.

The invention is particularly suited for placing long concrete pedestalpiles. The shell of along pile is formed and has the'characteristics ofthe shell hereinabove' described, with the exception that the portion ofthe shell above the expansible section may be composed of a series ofinexpansible casings which need not necessarily be pressure-tight withrespect to one another. The lower expansible casing 14 and theincxpansihle casing if) im- A pipe clamp 31 and ties 32 betweenmcdiately thereabove, as shown in FIG. 2, are constructed similarly tothe corresponding casings illustrated in FIG. 1. They are driven intothe'soii by the impact of a hammer on a core 34 having a drive foot 35which engages the shoe of the shell.

Annular rings 36. 37, 38 are welded to the exterior of? the core. Therings 37 and 3d are separated by an annular space containing a hollowdistendablc ring 39, which 2- is inflatable to establish a seal forisolating the leakproof chamber at the lower end of the shell.

The annular space between the rings 36 and 37 contains a plurality ofbladders 40 which are distributed around the core, as illustrated inFIG. 9. Each bladder is disposed between the core and a metal strip 41which is fastened at one end to an angle piece 42, anchored to the ring36. The other end of each strip 41 is fastened to another angle piece 43which is anchored to the ring 37. The strips may be installed with aninitial tension if desired, to restrain and protect the bladders 40 whenthe pile forming apparatus is lowered into the shell. The outer surfacesof the strips may be roughened or'provided with gritty material foratfording a high coefficient of friction when the strips are forced intocontact with the interior of the casing by pressure within the bladders.

Each bladder 40 is supplied with compressed air through a line extendinginto the shell, one of which is indicated at 44 in FIG. 2. The hollowring 39 is inflatable through a line 45 which connects with the ringfrom within the core 34.

Means for measuring the extent of expansion of the expansible casing 14are mounted on the lower end of the core 34. They comprise a pluralityof operative units 46, in such number as may be deemed desirable,angularly displaced from one another around the core. Collapsed units atdiametrically opposite sides of the core are shown in FIG. 2.

Each measuring unit 46 includes a scissors linkage con-' sisting of aseries of pairs of crossing pieces, each pair pivoted together in themiddle and connected with the next pair at the extremities. As shown inthe drawing, the extremity of one piece of the first pair of pieces ispivotaliy mounted at 47 on a cylinder 48, and an extremity 49 of theother piece of the same pair is pivotally attached to a piston 50. Thearrangement is such that the linkage is extended by inward movement ofthe piston. Extended positions of diametrically oppositely locatedlinkages are illustrated in FIG. 4.

Contact of the outermost end 51 of the linkage with the wall of theexpansible casing measures the radial position of the wall. This measureis indicated by the position of a piston in a master cylinder (notshown) located above ground and having lines 52 and 53 communicatingwith opposite ends of the cylinder 48. The master cylinder and pistonare operated to control the fiow of liquid through the lines to extendor contract the scissors linkage.

A similar measuring cylinder 55 containing a piston St is mounted on thefoot 35 at the bottom of the core. The ends of the cylinder 55 areconnected to the opposite ends of a master cylinder (not shown) locatedabove ground through lines 57 and 58, whereby the displacement of thepiston in the measuring cylinder 55 may be accurately ascertained. Thestem of the piston 56 is slidable through a hole in the drive foot 35.Upon moving the stem into contact with the bottom closure 12 the dislance between the foot and the closure can be ascertained. Because thechange in diameter of the pedestal casing is a function of the change inheight of. the pedestal casing, the measuring cylinder 55 can serve togauge the extent of expansion of the pedestal casing.

The pile-forming operation includes. mounting a prepared expansiblecasing to an upper casing and a closure, as explained in the foregoingdescription. This may be done in the field or at the factory. Then theassembled shell is driven into the ground until a load-bearing strata isreached. The driving core is then raised to a position where the radiusmeasuring devices 46 are located at upproximatcly the predeterminedlevel of the maximum girth of the extensible wall of the casing, asshown in MG. 3. This position is determined above ground by the positionof the piston in the master cylinder which is connected with themeasuring cylinder 55.

The mandrel bladders 4d are then inflated to hold or secure the corefirmly in fixed position relatively to the pansible casing. Hydraulicpressure may also be used as an expanding pressure medium. As this isbeing accomplished, the degree of expansion can be followed by use ofthe scissors linkages 46 and controlled master cylinders above theground.

Expansion continues until the expansible casing has reached a girthencompassing the desired bearing area for the pedestal. The liftingforce on the core caused by the pressurized fluid is resisted by theweight of the core and the friction eifective between the expandedmandrel and the shell and this downward force can be augmented by theweight of a hammer 33.

After the form for the pedestal has been completed, the pressurecontained within the expanded wall is relieved, the scissors linkagesare collapsed, and the mandrel bladders and sealing rings are deflated,whereupon the core and the attached appurtenances are withdrawn from theshell. If hydraulic pressure means have been employed, the liquid isremoved from the pile shell. The shell is then filled with concrete 6!),as shown in FIG. 5.

Either a gas or a liquid is used as the pressure exerting medium. Theemployment of hydraulic pressure offers several advantages. Anincompressible fluid, such as water, enables determination of the extentof expansion of the pedestal casing by measuring the quantity of thefluid used. Also, the energy consumed in increasing the pressure of anhydraulic fluid is expended almost entirely on enlarging the pedestalcasing in contradistinction to the loss of energy entailed incompressing a larger volume of air, as when an entire shell or most of ashell is sealed by an apparatus in the nature of that shown in FIG. 1,for example. The energy consumed in compressing'the gas above thepedestal casing performs no useful work. Particularly in the applicationof the method for forming a pedestal on along pile shell, as describedwith reference to FIGS. 2, 3 and 4, for example, this disadvantage ofpneumatic pressure is overcome because a core may be used as an elementof a'sealing plug or temporary closure whereby the pressure-tightchamber encompassed by the pedestal casing is isolated from theremainder of the pile shell. The choice of the fluid medium is largelydependent on which fluid medium will serve most. efiiciently andeconomically to bring about the results desired.

While the invention herein shown and described is adapted to fulfill theobjects primarily stated, it is to be understood that it is not intendedto confine the invention to the use of the specific forms of apparatusherein disclosed, for it is susceptible of embodiment in various mannersall coming within the scope of the claims which follow.

What is claimed is:

l. The method of making a concrete pedestal pile with a metallicimpermeable pile shell comprising a fluid-tight expan'sible tubularpedestal casing with folds extending continuous for substantially theheight of the casing, said pedestal casing completely closed at itslower end and having its upper end fixedly and hermetically connected toa tubular fluid-tight rigid casing, said method comprising inserting amandrel into the pile shell and driving the pile shell into the soil toa desired depth, establishing a seal interiorly of the shell between themandrel and the rigid casing and thereby creating a fluid-tight chamberencompassed by the pedestal casing, expanding the wall of the pedestalcasing with pressurized iluid within the chamber whose intensity ofpressure exceeds the passive resistance ofthe soil at the elevation ofthe pedestal casing, continuing the expansion of the wall of thepedestal casing with pressurized lluid until the pedestal casing isvertically arched outwardly into a sell-sustaining bulbous structure,relieving the pressure in the chamber, removing the seal between themandrel and the rigid casing, withdrawing the mandrel and removing thepressurizing fluid and filling the pile shell with concrete to completethe forming of the pedestal pile.

2. The method of making a concrete pedestal pile with a metallicimpermeable pile shell comprising a fluid-tight expansible tubularpedestal casing having folds extending continuous for substantially theheight of the casing, said pedestal casing completely closed at itslower end and having its upper end fixedly and hermetically connected toa tubular fluid-tight rigid casing, said method comprising driving thepile shell into the soil to a desired depth, sealing oil the lowerportion of the pile shell above the pedestal casing to render the lowerportion of the pile shell fluid-tight, subjecting the interior of thesealedoff lower portion of the shell to fluid under pressure and therebyexpanding the wall of the pedestal casing beyond the girth of the rigidcasing, measuring the diameter of the maximum girth of the expandedpedestal casing while maintaining pressure in the sealed-0H lowerportion of the shell, continuing the expanding pressure and measuringuntil the pedestal casing has been expanded into a vertically archedself-sustaining bulbous structure, and removing the pressurizing fluidand filling the pile shell with concrete to complete the forming of thepedestal pile.

3. A method for making a concrete pedestal pile within a pile shell byusing a shell comprising an impermeable, relatively rigid andinexpansible tubular metallic casing open at its upper end and havingits lower end hermetically joined to an impermeable expansible tubularmetallic casing completely closed at its lower end, said methodcomprising the steps of driving the pile shell into the ground, sealingoil the interior of the expansible casing by sealing the pile shellabove the expansible casing to make the interior of the shellabove theclosed lower end of the expansible casing available as a fluid-tightchamber for containing fluid under pressure, filling the fluid-tightchamber with a fluid under pressure, expanding the expansible casing byincreasing the pressure of the fluid contained by the fluid-tightchamber and thereby forming the expansible casing into a bulbousstructure self-sustaining against the inwardly directed pressure of Vthe soil surrounding the bulbous structure, relieving the pressure ofthe fiuid, removing the previously applied seal of the shell and therebymaking the entire interior of the shell accessible from its upper end,removing the fiuid and introducing into the shell a suificient quantityof concrete to fill the shell and form, upon hardening, an integratedpedestal pile having a concrete pedestal within the expanded casingwhich is conterminous with the expanded interior surface of the expandedmetallic casing.

5. The method according to claim 3 wherein a compressed gas is employedfor expanding the expansible casing.

5'. The method according to claim 3 wherein a pressurized liquid is usedfor expanding the expansible mota r lie casing and the liquid is removedfrom the interior of the fluid-tight chamber before the shell is filledwith concrete.

6. In a pile shell, a pedestal casing, arelatively inexpansible rigidring at each end of said pedestal casing, said pedestal casingcomprising an impermeable metallic sleeve crimped with deep foldsrunning longitudinally of the sleeve to adjacent an annulus at each endof sleeve, each annulus formed by contiguous parts of the folds laidover onto one another whereby the outside diameter of the annuli is lessthan the maximum outer diameter or" the sleeve between the annuli, theoutside of one of said annuli engaging the inside of one of said rings,and the outside of the other of said annuli engaging the inside of theother of said rings, means pcrmanently joinning said annuli at the endsof said sleeve to said rings and sealing against leakage at the jointsbetween the sleeve and the rings, a tubular shaft casing having a lowerend fixedly attached to one of said ringsin sealing relationshipthroughout the circumference of the ring, a fluid-tight closure meansfixedly attached to the other of said rings and closing the lower end ofsaid pedestal casing, and means sealing against leakage at the jointurebetween 'said pedestal casing and said closure.

7. In a pile shell in situ, a metallic shell comprising a hollow uppersection and a 'hollow lower section with adjoining ends fixedlyconnected together and hermetically sealed throughout theircircumference, said upper section comprising a pile casing which isrelatively rigid and inexpansible laterally, said lower sectioncomprising an impermeable ribbed wall of sheet metal vertically archedoutwardly intermediate the upper and lower. ends of the lower section,said wall forming a bulbous structure selfsustaining against theinwardly acting pressure of the soil surrounding the bulbous structure,said wall having longitudinally extending folds, alternately reversedtransversely around the wall and varying in depth from deep foldsadjacent the ends of the lower section to shallow folds as the distanceincreases from the ends of the lower section to the maximum girth of thelower section, impermeable metallic closure means closing the lower endof said lower section, and means hermetically sealing against leakagebetween said closure means and said ribbed wall.

8. A pile in situ, said pile comprising the pile shell according toclaim 7 containing a filling of concrete.

References Cited by the Examiner UNITED STATES PATENTS 961,492 6/10Goldsborough 61-5 3.6 1,296,995 3/ 19 Miller 61-53.6 1,827,015 10/31Jenkins 61-5332. 2,497,377 2/50 Swann 61--53.6 2,741,093 4/56 Riker6153.72 2,876,413 3/59 Saurenman.

3,005,315 10/61 Cobi 6153.72 3,046,601 7/62 Hubbert et al. 166-4 FOREIGNPATENTS 703,654 2/54 Great Britain. 292,903 7/ 16 Germany.

EARL I. WITMER, Primary Examiner.

WILLIAM I. MUSHAKE, JACOB L. NACKENOFF, Examiners.

6. IN A PILE SHELL, A PEDESTAL CASING, A RELATIVELY INEXPANSIBLE RIGIDRING AT EACH END OF SAID PEDESTAL CASING, SAID PEDESTAL CASINGCOMPRISING AN IMPERMEABLE METALLIC SLEEVE CRIMPED WITH DEEP FOLDSRUNNING LONGITUDINALLY OF THE SLEEVE TO ADJACENT AN ANNULAR AT EACH ENDOF THE SLEEVE, EACH ANNULAR FORMED BY CONTIGUOUS PARTS OF THE FOLDS LAIDOVER ONTO ONE ANOTHER WHEREBY THE OUTSIDE DIAMETER OF THE ANNULI IS LESSTHAN THE MAXIMUM OUTER DIAMETER OF THE SLEEVE BETWEEN THE ANNULI, THEOUTSIDE OF ONE OF SAID ANNULI ENGAGING THE INSIDE OF ONE OF SAID RINGS,AND THE OUTSIDE OF THE OTHER OF SAID ANNULI ENGAGING THE INSIDE OF THEOTHER OF SAID RINGS, MEANS PERMANENTLY JOINING SAID ANNULI AT THE ENDSOF SAID SLEEVE TO SAID RINGS AND SEALING AGAINST LEAKAGE AT THE JOINTSBETWEEN THE SLEEVE AND THE RINGS, A TUBULAR SHAFT CASING HAVING A LOWEREND FIXEDLY ATTACHED TO ONE OF SAID RINGS IN SEALING RELATIONSHIPTHROUGHOUT THE CIRCUMFERENCE OF THE RING, A FLUID-TIGHT CLOSURE MEANSFIXEDLY ATTACHED TO THE OTHER OF SAID RINGS AND CLOSING THE LOWER END OFSAID PEDESTAL CASING, AND MEANS SEALING AGAINST LEAKAGE AT THE JOINTUREBETWEEN SAID PEDESTAL CASING AND SAID CLOSURE.